Ferromagnetic interaction in iron(II)–bis-Schiff base complexes

Iron(II) Mediated Supramolecular Architectures with Schiff Bases and Their Spin-Crossover Properties

Supramolecular architectures, which are formed through the combination of inorganic metal cations and organic ligands by self-assembly, are one of the techniques in modern chemical science. This kind of multi-nuclear system in various dimensionalities can be implemented in various applications such as sensing, storage/cargo, display and molecular switching. Iron(II) mediated spin-crossover (SCO) supramolecular architectures with Schiff bases have attracted the attention of many investigators due to their structural novelty as well as their potential application possibilities. In this paper, we review a number of supramolecular SCO architectures of iron(II) with Schiff base ligands exhibiting varying geometrical possibilities. The structural and SCO behavior of these complexes are also discussed in detail.

Assembly of High-Spin [Fe3] Clusters by Ligand-Based Multielectron Reduction

The hexanuclear [Na₁₂Fe₆(tris-cyclo-salophen)₂(THF)₁₄], 1-THF, and the trinuclear [Na₆Fe₃(tris-cyclo-salophen)(py)₉], 1-py, Fe(II) clusters can be easily assembled in one step from the ligand-based reduction of the [Fe^II(salophen)(THF)] complex. These complexes consist of triangular cores where three Fe(II) ions are held together, within range of bonding interaction, by the hexa-amide, hexaphenolate macrocyclic ligand tris-cyclo-salophen^12-. The tris-cyclo-salophen^12- ligand is perfectly suited for binding three Fe(II) centers at short distances, allowing for strong magnetic coupling between the Fe(II) centers. The macrocyclic ligand is generated by the reductive coupling of the imino groups of three salophen ligands, resulting in three new C-C bonds. The six electrons stored in the ligand become available for the reduction of carbon dioxide with selective formation of carbonate.